Device and method for skin laser treatment

ABSTRACT

The system for treating a region of the epidermis, comprising: —at least one laser energy source; —a time control device to generate a laser beam; —a laser energy focusing system arranged and produced to direct a laser beam on said region of the epidermis. The control device generates a laser beam comprising a plurality of composite pulses, emitted at a base frequency, each composite pulse comprising a sequence of sub-pulses at a higher frequency than said base frequency.

TECHNICAL FIELD

The present invention relates to a device and a method for skintreatment. More in particular, the present invention relates to a deviceand a method for treatment using an apparatus comprising a laser beam ofsuitable wavelength, optionally combined with an RF current, to obtaingiven effects on the epidermis, such as wrinkles reduction and a generalrejuvenating effect.

BACKGROUND OF THE INVENTION

Medical and cosmetic treatments to improve the appearance of the person,to solve problems related to skin blemishes and also to deal with andsolve situations of true psychological distress deriving from thesubject's inability to accept his or her appearance, are becomingincreasingly widely used.

Among the various procedures, methods and machines used, a vast numberof cases are dedicated to treatments aimed at reducing the effects ofaging and, therefore, in particular, at eliminating or reducing theformation of wrinkles on the face and on other parts of the body, suchas the neck and the upper part of the chest. In recent times, techniqueshave been developed for treating the epidermis using laser. In manyapplications, the portion of epidermis to be treated is irradiated in apractically uniform manner by a laser beam, which performs a surfaceablation process, with consequent elimination of the upper layers of theepidermis.

The use of the laser in treatment of the epidermis, especially of theface, to reduce wrinkles and other skin blemishes is described, amongothers, in the following works: Chernoff G, Slatkine M, Zair AND, MeadD., “SilkTouch: a new technology for skin resurfacing in aestheticsurgery”, in J Clin Laser Med Surg. 1995 April; 13(2):97-100; Waldorf HA, Kauvar A N, Geronemus R G; “Skin resurfacing of fine to deep rhytidesusing a char-free carbon dioxide laser in 47 patients.”, in DermatolSurg. 1995 November; 21(11):940-6; David L M, Same A J, Unger W P.,“Rapid laser scanning for facial resurfacing.”, in Dermatol Surg. 1995December; 21(12):1031-3; Lask G, Keller G, Lowe N, Gormley D., “Laserskin resurfacing with the SilkTouch flashscanner for facial rhytides.”,in Dermatol Surg. 1995 December; 21(12):1021-4; Apfelberg D B.,“Ultrapulse carbon dioxide laser with CPG scanner for full-faceresurfacing for rhytids, photoaging, and acne scars”, in Plast ReconstrSurg. 1997 June; 99(7):1817-25; Apfelberg D B, Smoller B. “UltraPulsecarbon dioxide laser with CPG scanner for deepithelialization: clinicaland histologic study”, in Plast Reconstr Surg. 1997 June; 99(7):2089-94;Raulin C, Drommer R B, Schönermark M P, Werner S., “Facialwrinkles—ultrapulsed CO2 laser: alternative or supplement to surgicalface lift?”, in Laryngorhinootologie. 1997 June; 76(6):351-7; Trelles MA, Rigau J, Mellor T K, García L., “A clinical and histologicalcomparison of flashscanning versus pulsed technology in carbon dioxidelaser facial skin resurfacing”, in Dermatol Surg. 1998 January;24(1):43-9; Weinstein C., “Computerized scanning erbium:YAG laser forskin resurfacing”, in Dermatol Surg. 1998 January; 24(1):83-9; BernsteinL J, Kauvar A N, Grossman M C, Geronemus R G., “Scar resurfacing withhigh-energy, short-pulsed and flashscanning carbon dioxide lasers”, inDermatol Surg. 1998 January; 24(1):101-7; Vaïsse V, Clerici T, FusadeT., “Bowen disease treated with scanned pulsed high energy CO2 laser.Follow-up of 6 cases”, in Ann. Dermatol. Venereol. 2001 November;128(11):1220-4.

In recent times, methods have been developed in which treatment of theepidermis is discontinuous (known as “fractional” technology), i.e. on agiven region to be treated the laser is focused in discrete areas,separated from one another by areas that are not irradiated by the laserbeam. The zones irradiated by the laser beam are subjected to ablationin substantially cylindrical volumes, spaced apart from one another bylarge volumes in which no treatment is carried out. Methods of this typeare described in Toshio Ohshiro et al, “Laser Dermatology—State of theArt”, proceedings of the 7th Congress International Society for LaserSurgery and Medicine in Connection with Laser 87 Optoelectronics, ed.Springer-Verlag, 1988, page 513 ff. The same methods are described inU.S. Pat. No. 6,997,923.

In this way, attempts are made to combine the requirement of tissueablation, which causes localized damage of the tissue and erythema dueto the noteworthy heating produced by the laser, with the need for aminimally invasive procedure. It was deemed that by acting on limitedtissue portions spaced apart from one another by wide zones not affectedin by the laser beam, it would be possible to obtain treatment effects(such as reduction or elimination of wrinkles) equivalent to thoseobtained with a full volume or full surface area treatment ofconventional type, but with fewer secondary effects of damage to theepidermis, a decrease in the formation of erythema and in general areduction in post-treatment recovery times.

In the literature, procedures of this type are described, among others,in the following works: Fitzpatrick R E, Rostan E F, Marchell N.,“Collagen tightening induced by carbon dioxide laser versus erbium: YAGlaser”, in Lasers Surg. Med. 2000; 27(5):395-403; Hasegawa T, MatsukuraT, Mizuno Y, Suga Y, Ogawa H, Ikeda S., “Clinical trial of a laserdevice called fractional photothermolysis system for acne scars”, inDermatol. 2006 September; 33(9):623-7; Rahman Z, Alam M, Dover J S.,“Fractional Laser treatment for pigmentation and texture improvement”,in Skin Therapy Lett. 2006 November; 11(9):7-11; Laubach H, Chan H H,Rius F, Anderson R R, Manstein D., “Effects of skin temperature onlesion size in fractional photothermolysis”, in Lasers Surg Med. 2007January; 39(1):14-8; Collawn S S., “Fraxel skin resurfacing”, in AnnPlast Surg. 2007 March; 58(3):237-40; Hantash B M, Bedi V P, Chan K F,Zachary C B., “Ex vivo histological characterization of a novel ablativefractional resurfacing device”, in Lasers Surg Med. 2007 February;39(2):87-95; Hantash B M, Bedi V P, Kapadia B, Rahman Z, Jiang K, TannerH, Chan K F., “In vivo histological evaluation of a novel ablativefractional resurfacing device”, in Lasers Surg Med. 2007 February;39(2):96-107.

The efficacy of these methods is debatable. In particular, acting onvolumes that are too close together it is not possible to obtainparticular improvements in terms of reduction of recovery times, whiletreating volumes that are spaced too far from one another by untreatedzones involves the risk of insufficient results and consequent need fora second treatment.

The use of radiofrequency current is also known in aesthetic treatments.See for example Goldberg D J, Fazeli A, Berlin A L. “Clinical,laboratory, and MRI analysis of cellulite treatment with a unipolarradiofrequency device”, in Dermatol Surg. 2008 February; 34(2):204-9; orMontesi G, Calvieri S, Balzani A, Gold M H., “Bipolar radiofrequency inthe treatment of dermatologic imperfections: clinicopathological andimmunohistochemical aspects”, in J. Drugs Dermatol. 2007 February;6(2):212-5.

WO-A-02/26147 and U.S. Pat. No. 6,702,808 describe a system fortreatment of the epidermis in which a radiofrequency current is combinedwith optical energy. The treatment described in this publicationprovides for the simultaneous application of optical and radiofrequencyradiation. The characteristics of the optical radiation used are notdescribed in detail, although it is indicated that their wavelength (λ)must be no greater than 1200 nm.

SUMMARY OF THE INVENTION

The object of the invention is to provide a technology that is theresult of a combination of different technologies according to preciserelations of proportionality both of time and space to obtain asynergistic effect, i.e. a treatment efficacy that exceeds the sum ofthe results obtainable with the different technologies separately.

Typical applications concern aesthetic skin treatments, in particularwith the object of obtaining a reduction of wrinkles, tightening andoverall rejuvenation of the tissue. Therefore, the invention alsorelates to cosmetic treatment methods of the skin and of the underlyingtissue through application of optical laser radiation.

In particular, compared to conventional resurfacing the fractionaltechnology used to date has the advantage of having a much lesscomplicated postoperative course, at the same time ensuring excellentrecovery of skin texture, reduction of porosity, increased brightnessand elasticity. The limit of these technologies consist in their poorefficacy on loose skins, for which it is not possible to stimulate toany significant extent the deep structures of the dermis, without usingoverly aggressive parameters, which go against the minimally invasiveapproach inherent to fractional technology.

From the international literature and the patent bibliography it can beseen how the formation of plasma with CO₂ laser is dependent on the timeshape of the pulse. In order to transfer an appropriate heat wave to thereticular dermis while preventing the onset of undesirable side effects,the invention is based on a new time distribution of the energy in thepulses that takes account of the physical laws for the formation ofplasma and therefore of plasma mediated ablation.

According to one aspect, to solve problems of the prior art, eithercompletely or in part, the invention provides a system for the treatmentof a region of the epidermis comprising:

-   -   at least one laser energy source;    -   a time control device to generate a laser beam;    -   a laser energy focusing system arranged and designed to direct a        laser beam on said region of the epidermis;        wherein said control device generates a laser beam comprising a        plurality of composite pulses, emitted at a base frequency, each        composite pulse comprising a sequence of sub-pulses at a higher        frequency than said base frequency.

According to a different aspect, the invention relates to a cosmeticmethod for treating a portion of epidermis of a patient, comprising thestep of emitting a laser beam comprising one or more composite pulses,emitted at a base frequency, each composite pulse comprising a sequenceof sub-pulses at a higher frequency than said base frequency.

The composite pulse can advantageously comprise a pre-pulse at a higherfluence and one or more subsequent sub-pulses at a lower fluence. Thelaser pulses can be combined with the application of radiofrequencycurrent.

The term “focusing system” is intended both as a dynamic system,comprising a scanning device, to move the beam to different positions,and as a static system, where an appropriate optic divides, for example,an initial beam into a plurality of adjacent beams arranged according toan appropriate pattern, for example according to a matrix.

In some embodiments of the invention, the laser energy focusing systemis arranged and controlled to treat contiguous volumes of the epidermisdistributed according to a pattern, wherein each volume treated has acenter substantially positioned on the axis of the laser beam used totreat said volume, the axes of the laser beams used to treat saidcontiguous volumes being distributed according to a presettable matrixof points.

Given a portion of epidermis to be treated, this can be irradiatedsimultaneously by a plurality of beams, for example obtained withparticular optics from a single beam. The various beams are, forexample, arranged according to an appropriate pattern, for example amatrix. Preferably, however, a single beam or even more than one beamcan be used, to which a scanning movement is imparted according tocoordinates (for example Cartesian or polar). In some embodiments,emission of the laser pulse is controlled so that single pulses of laserenergy are “fired” in sequentially variable positions along a pre-setpattern, for example according to the points of a matrix.

In other embodiments, the laser beam can be moved from one position tothe other without interrupting the energy emission, providing asufficiently short time for moving from one treatment position to theother. In this way, the effect of the laser during movement from oneirradiation point to the other is substantially negligible when comparedwith the effect of the beam during the dwell phase in a given point orposition of the irradiation pattern.

In all cases adjacent beams (irradiated simultaneously, or sequentiallywith a scanning system) can have overlapping zones, i.e. zones in whichthe effect of two adjacent beams (or also three or more adjacent beams)are overlapped and summed. Naturally, also as a function of the scanningor multiple beam operation and, in the first case, of the scanning time,space overlapping only or else space and time overlapping of beams mustbe taken into account.

According to a further aspect, the invention relates to a system fortreating a epidermis region, comprising:

-   -   at least one laser energy source to generate a pulsed laser        beam;    -   a laser energy focusing system arranged and designed to direct a        laser beam on said region of the epidermis;    -   a radiofrequency current source with at least one electrode for        applying the radiofrequency current;    -   at least one control device which controls the laser energy        source and the radiofrequency current source so as to emit said        laser beam and said radiofrequency current in a timely        coordinated manner.

In some embodiments the control device is designed to emit theradiofrequency current in a time interval at least partly overlapping atime interval of emission of the pulsed laser beam and/or in a timeinterval subsequent to a time interval of emission of the pulsed laserbeam.

Further advantageous features and embodiments of the invention aredescribed hereunder and are indicated in the appended claims, which forman integral part of the present description. The brief descriptionprovided above identifies characteristics of the various embodiments ofthe present invention so that the following detailed description can bebetter understood and so that the present contributions to the art maybe better appreciated. Naturally, there are other characteristics of theinvention which will be described below and will be set forth in theappended claims. With reference to this, before illustrating differentembodiments of the invention in detail, it must be understood that thevarious embodiments of the invention are not limited in theirapplication to the structural details and to the arrangements ofcomponents described in the following description or illustrated in thedrawings. The invention can be implemented in other embodiments andimplemented and put into practice in various ways. Moreover, it must beunderstood that the phraseology and terminology employed herein arepurely for descriptive purposes and must not be considered limiting.

Therefore, those skilled in the art will understand that the concept onwhich the description is based can be readily used as a basis to designother structures, other methods and/or other systems to implement thevarious objects of the present invention. Consequently, it is importantthat the claims are considered as inclusive of those equivalentstructures which do not depart from the spirit and from the scope of thepresent invention.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will be better understood by following the description andaccompanying drawing, which shows practical non-limiting embodiments ofthe invention. More in particular:

FIG. 1 shows a diagram of a device embodying the invention;

FIG. 2 shows a detail of the handpiece of the device of FIG. 1;

FIG. 3 shows a diagram of a laser-beam scanning system;

FIG. 4 shows a diagram of a system for dividing a main laser beam in aplurality of adjacent or contiguous laser beams;

FIG. 5 shows a matrix according to which the laser treatment points of aportion of epidermis can be arranged;

FIG. 6 schematically shows an improved handpiece for combined laser andradiofrequency treatment;

FIGS. 6A, 6B, 6C and 6D schematically show an improved embodiment of anelectrode for applying radiofrequency current;

FIG. 7 shows the use of the handpiece of FIG. 6;

FIGS. 8 and 9 show the shape of the laser pulse in two differentembodiments;

FIGS. 10A-10K show histological images of tissues treated with twodifferent types of laser pulses according to the invention in differentapplication conditions;

FIGS. 11A, 11B, 12A, 12B, 12C show a schematic representation of theeffect of ablation and of thermal shock in the tissue treated withdifferent types of laser pulses according to the invention;

FIG. 13 shows a diagram of the conductivity of the tissue as a functionof the frequency of a radiofrequency electrical current;

FIGS. 14A-14E show diagrams of the trend over time of hemoglobin in atissue treated with laser pulses according to the invention with andwithout application of radiofrequency electrical current;

FIG. 15 shows a diagram illustrating the shrinkage effect provoked bythe different types of treatment;

FIG. 16 shows a diagram illustrating the speed of disappearance of skinreddening caused by the treatment in various treatment conditions;

FIG. 17 shows a diagram relating to the formation of plasma as afunction of the density of emitted laser energy;

FIG. 18 shows a time diagram explaining the biological phenomenaprovoked by the combined application of optical energy in the form oflaser radiation and electrical energy in the form of radiofrequencycurrent.

DETAILED DESCRIPTION OF EMBODIMENTS OF THE INVENTION

Structure of the Handpiece and of the Optics

The following detailed description of exemplary embodiments refers tothe accompanying drawings. The same reference numbers in differentdrawings identify identical or similar elements. Moreover, the drawingsare not necessarily in scale. Further, the following detaileddescription does not limit the invention. Rather, the scope of theinvention is defined by the appended claims.

Reference in the whole of the description to “an embodiment” or “theembodiment” or “some embodiments” means that a particular feature,structure or element described in relation to an embodiment is includedin at least one embodiment of the subject described. Therefore, thephrase “in an embodiment” or “in the embodiment” or “in someembodiments” in various points throughout the description does notnecessarily refer to the same embodiment or embodiments. Moreover, theparticular features, structures or elements can be combined in anysuitable manner in one or more embodiments.

FIGS. 1 and 2 show a device in which the invention can be incorporated.In general, the device 1 comprises a base 3, wherein at least one lasersource 5 is housed. The laser source 5 can be a continuous laser, butpreferably a pulsed laser is used. The block indicated generically with5 is intended also as including a system to control the emission in timeof the laser radiation, i.e. the pulse generation system.

According to some embodiments, the laser source can have an emittingwavelength comprised between 532 and 13,000 nm and more in particular awavelength of 10600 nm, corresponding to CO₂ laser emission. In fact,the laser source is preferably a CO₂ laser.

In some modes of use, the laser can be controlled so as to provide apulse for each position or point of a treatment pattern. However, inother modes of use more than one laser pulse can be “fired” for eachoperating position, i.e. at each point treated. For example, from two tofive pulses can be provided for each position of the laser. Preferably,the laser is controlled so as to be able to emit one or more pulses foreach position or point of the pattern on the portion of epidermis to betreated, depending on the settings chosen by the operator. Movement ofthe laser beam can be obtained through a system of scanning mirrorsdescribed in greater detail below. Preferably, the laser emission isinterrupted when moving from one treatment position to the other, i.e.from one point to the other of a treatment pattern.

Advantageously, in some embodiments the laser beam has a Gaussian powerdistribution, with a maximum power density at the center and decreasingtoward the periphery of the cross section of the beam. To obtain theGaussian shape of the beam, in some embodiments the laser cavity isproduced so as to isolate the fundamental propagation mode and thefocusing optics must be designed to contribute to maintaining theGaussian shape of the energy distribution when moving from the axisoutwardly. An appropriate choice of cavity diameter and an appropriateradius of the mirrors of the laser source are able to provide generationof the TEM00 oscillation mode that provides a Gaussian beam profile.

The laser beam can be conveyed through a waveguide 7 toward a handpiece9. The guide can be designed in various ways, also depending upon thefrequency and the emission power of the laser. In the exampleillustrated the waveguide is simply made of hollow tubular elements,joined to one another and inside which mirrors for deflecting the laserbeam are arranged to deviate the beam along the axis of the varioustubular portions of the guide.

Inside the handpiece 9 there are arranged focusing systems and/orscanning of the laser beam, some of which are represented schematicallyin FIGS. 3 and 4. Preferably in the handpiece 9 there is contained ascanning system (FIG. 3) comprising for example two scanning mirrors 21with related actuators 23 controlled electronically by a control unit,not shown. The scanning mirrors control the movement of the laser beam Foutput from the handpiece 13, so that it follows a given path, accordingto criteria better defined below. Therefore, in this case a single laserbeam F is outputted from the handpiece and directed toward the surfaceof the epidermis to be treated, from which the handpiece can be held ata constant distance, for example by means of a spacer 11. On thehandpiece 13 push buttons, knobs or other adjustment and interfacemembers can be arranged, schematically indicated with 15, through whichthe operator can modify the shape of the beam and/or the dimension andthe area of the scanning surface, the movement of the beam and the like.

Through the handpiece 13 and the scanning system contained therein it ispossible to control movement of the beam F according to a defined andstored pattern, optionally modifiable by the user.

In a suitable position along the path of the laser beam a focusing opticis arranged. In the diagram of FIG. 3 said optic is indicated with 25and is placed in the handpiece, but it must be understood that this isnot strictly necessary and that other positions are possible. The optic25 also has the function of imposing on the beam a given energy densitydistribution as a function of the radius, as will be clarified below.

In other embodiments, inside the handpiece 13 there are arrangedfocusing systems which divide the laser beam into a plurality of beamsadjacent to one another and which impart to each of the adjacent beamsan energy density profile as a function of the radius according to thecriteria described below.

In some embodiments the lens placed in the handpiece in combination withthe shape of the beam generated by the source give rise to a Gaussianenergy density distribution profile. The shape of the beam generateddepends on the purity of the propagation mode inside the laser cavitywhich consequently determines the energy distribution transverse to theaxis of propagation in the free space at the output of the laser source.

In some embodiments the beams with which the portion of epidermis to betreated is irradiated can be adjacent beams generated with an opticalsystem of the type represented in FIG. 4, or can simply be representedby positions assumed in time sequence by a same laser beam which ismoved by a scanning system as represented in FIG. 3. In this lattercase, the laser beam is preferably switched on, i.e. activatedsequentially in each position desired according to a radiation pattern,while during movement between one point and the other the laser ispreferably switched off.

Whatever the system for generating the adjacent laser beams, theepidermis can be irradiated, for example, following a pattern with amatrix of points, as indicated schematically in FIG. 5. The letter Egenerically indicates a treated portion of epidermis and the letter Fthe points of intersection between the axis of the laser beam and thesurface of epidermis being treated. It must be observed that in thiscase the treatment pattern is formed by a plurality of points arrangedaccording to a matrix or grid with rectangular mesh, the vertices ofwhich form the points in which the center of the laser beam ispositioned. One or more laser pulses can be emitted in each positionrepresented by a point F.

It must be understood that the pattern of FIG. 5 is provided purely byway of example and that different patterns can be used, for exampleaccording to a matrix with rhomboidal mesh, or also a pattern in whichthe points F are arranged according to curved lines, according to aspiral or in any other way. Currently, a pattern according to a matrixwith quadrangular, i.e. rectangular or rhomboidal, mesh is preferred.

The shape of the laser pulses used and the values of the emissionparameters, and the results obtained with various shapes of laserradiation will be discussed below.

According to improved embodiments of the invention, the laser treatmentis combined with a treatment through applying radiofrequency. FIGS. 6and 7 illustrate this embodiment. FIG. 6 shows a handpiece 109, whichcontains the same components as the handpiece 9, in addition to aradiofrequency generator, indicated schematically with 110. Theradiofrequency generator is connected to a pair of electrodes 113. Insome embodiments the electrodes 113 are shaped to form a spacer betweenthe handpiece 109 and the surface to be treated. The distance isdetermined on the basis of the optical characteristics of the laser,whose radiation is conveyed to the handpiece 109 through a light guide115, as in the embodiment described previously. Interface means betweenthe appliance and the user are provided on the handpiece 109, such asone or more push buttons or the like, generically indicated with 117.

Using the electrodes as spacers, an instrument that is particularlycompact, inexpensive and easy to use is obtained.

With a handpiece of this type it is possible to synergistically combinethe effects of laser and of radiofrequency on the treated tissue. Whenthe electrodes 113 are resting on the skin to be treated, for example onthe patient's face, as shown in FIG. 7, the radiofrequency fieldgenerated by the electrodes propagates into the tissues and generatesinduced currents, which heat the treated tissue.

FIGS. 6A, 6B, 6C and 6D schematically show an improved embodiment of anelectrode for applying radiofrequency current which prevents or reducesthe risk of generating electrical arcs between the electrode and theepidermis of the subject treated when the electrode is moved away fromthe skin. In this embodiment a device is provided for switching off theelectrical power circuit of the RF current, which opens the circuit andcuts off the electrical power inside a protected zone, preventingelectrical discharges from generating on the skin. In particular, theelectrode 113 can have ends 113A (FIG. 6D) seated in respective cases114. The ends 113A form first contacts cooperating with second contacts118 housed in the respective cases 114. The contacts 113A, 118 form apair of switches which are closed as a result of compression ofrespective springs 120, advantageously housed in the cases 114, when theelectrode 113 is pressed against the skin. Compression of the springs120 causes the ends 113A of the electrode 113 to contact the contacts118, closing the electrical circuit. When the operator moves thehandpiece 109 on which the electrodes 113 are placed away from thepatient's skin, the springs 120 extend, causing the contacts 113A, 118to move away from each other and consequent opening of the electricalcircuit. Any arcs o discharges remain confined inside the cases 114.

It must be understood that an electrode 113 with one movable end 113Aand the other end permanently connected to the electrical circuit couldalso be used. The elastic effect can also be obtained by means ofproperties of the material with which the electrode 113 is made, withoutthe need to use an auxiliary spring. For example, the electrode 113 canbe made in the form of flat spring, with an advantageously arcuateshape. One end of electrode is fixed and the other forms a movablecontact which approaches a fixed contact, enclosed in a protected zone,when the handpiece is pressed onto the skin, closing the electricalcircuit.

Alternatively to the use of movable contacts, or in combinationtherewith, a sponge 116, either made of conducting material orpreferably made conductive by impregnating it with a conductive liquid,such as a saline solution, can be associated with the electrode 113. Thesponge 116 can be shaped appropriately, for example with a groove, to bereversibly fixed to the electrode 113. The sponge 116 can advantageouslybe disposable, for reasons of hygiene.

Laser radiation and radiofrequency can be combined or overlapped in timein various ways, according to criteria that will be clear from thedescription set forth below.

The results of the combined application of optical radiation and RFcurrent and some possible explanations of the particular efficacyobtainable with this method will be discussed below.

Time Shape of the Laser Beam

It has been discovered, and is an important element of the presentinvention, that particular shapes of the pulse of the laser radiation,i.e. particular trends over time of the pulsed laser emission, enablemuch greater biological effects to be obtained on tissue, compared toprior art systems. It has also been discovered that in some cases thelaser pulses shaped according to the invention have a synergistic effectin combination with a radiofrequency current. As will be illustratedbelow, the shapes of the pulses according to the invention enable moreefficient treatments and faster healing, especially in skin-tissuerejuvenating and firming treatments.

FIG. 8 shows a first time shape of a series of laser pulses according tothe invention, i.e. the trend over time of the laser light emission. Inthis figure, the abscissa indicates the time and the ordinate indicatesthe emitted power.

Hereinafter the laser pulse having the shape of FIG. 8 will be indicatedas “pulse S”. Said pulse is in fact a composite pulse, where compositepulse is intended as a pulse that is in turn constituted by thecombination of sub-pulses, or hypo-energy pulses, as will be describedin detail below.

FIG. 8 shows a sequence of pulses SP with the period T. A period T hasan on interval τ-on and an off interval τ-off. The sum of the timeintervals τ-on and τ-off is equal to the period T of the pulse. Therelation τ-on/T is defined as the duty cycle of the composite pulse. Theinverse 1/T of the period T of the composite pulse is defined as thefrequency of the composite pulse. According to some embodiments, thefrequency of the composite pulse, hereinafter also defined as basefrequency, is comprised between 1 and 1000 Hz, for example between 1 and500 Hz. The duty cycle of the composite pulse can be comprised between1% and 90% and preferably between 2% and 50% and even more preferablybetween 2% and 40%.

As can be observed in FIG. 8, sub-pulses Si are contained in theinterval τ-on of each composite pulse. In the embodiment of FIG. 8sub-pulses, all of the same duration, are contained in the intervalτ-on. In some embodiments the sub-pulses Si have a frequency comprisedbetween 1 kHz and 200 kHz. In preferred embodiments the frequency of thesub-pulses is comprised between 1 kHz and 100 kHz and even morepreferably between 2 kHz and 50 kHz. In some embodiments the frequencyis comprised between 5 and 45 kHz, for example between 8 and 40 kHz.

The duty cycle of the sub-pulses, i.e. the relation between the periodof the sub-pulse, indicated with Ts in FIG. 8, and the duration of theon-interval (during which sub-pulses are emitted) is determined as afunction of the peak power, of the duration τ-on of the composite pulseand of the energy per pulse that is required to be emitted at eachpulse. In some embodiments the on-duration of the single sub-pulse iscomprised between 1 and 50 microseconds and preferably between 2 and 40microseconds. In some embodiments, the duration of the on-period isbetween 3 and 25 microseconds. The duty cycle can be comprised between 1and 90% and preferably between 1 and 50% and even more preferablybetween 2 and 25%. Typically, the duty cycle is comprised between 3 and24%.

La peak power, indicated in FIG. 8, can be comprised between 10 and 200W, preferably between 40 and 190 W.

In some embodiments the energy per pulse of the composite pulses iscomprised between 0.2 and 200 mJ, for example between 0.4 and 150 mJ andpreferably between 0.4 and 130 mJ.

The energy of the single sub-pulse Si can be comprised between 0.2 and10 mJ and preferably between 0.4 and 8 mJ.

The spot area, i.e. the area of the section of the laser beam on thesurface onto which the beam is projected, is advantageously comprisedbetween 0.0001 and 0.0003 cm² and preferably between 0.00015 and 0.0002cm². The fluence, i.e. the energy per unit of surface area, is obtainedas the ratio between the powers and the spot areas indicated above.According to some embodiments the diameter of the spot is comprisedbetween 50 and 500 micrometers, preferably between 80 and 400micrometers, even more preferably between 100 and 200 micrometers, forexample around 150 micrometers.

The average power can be comprised between 2 and 100 W, for examplebetween 4 and 80 W, preferably between 4 and 50 W.

In some embodiments of the invention the number of pulses Si for eachtrain or composite pulse can be comprised between 1 and 100 andpreferably greater than 1 and less than or equal to 80.

The following tables 1 and 2 each indicate two series of values for themain parameters of the pulse. It must be understood that each parametermay vary in the interval defined by the two values of the correspondingline.

TABLE 1 Repetition frequency (Hz) 10,000 10,000 Duration of thesub-pulse (μs) 100 100 On time of the sub-pulse (μs) 4 24 Off time ofthe sub-pulse (μs) 96 76 Duty Cycle (%) of the sub- 4% 24% pulse Peakpower of the sub- 12 180 pulse (W) Energy of the sub-pulse (mJ) 0.4 6.0Total energy of the train of 0.4 120.0 pulses (mJ) Number of pulses pertrain 1 20 (i.e. per composite pulse) Spot diameter (μm) 150 150 Spotarea (cm²) 0.0001767146 0.0001767146 Fluence of the single sub- 2.2633.95 pulse (J/cm²) Fluence of the composite 2.26354 679.06109 pulse(J/cm²) Average power (W) 4 60 Dwell time (μs) 100 2000

TABLE 2 Repetition frequency (Hz) 40,000 40,000 Duration of thesub-pulse (μs) 25 25 On time of the sub-pulse (μs) 1 6 Off time of thesub-pulse (μs) 24 19 Duty Cycle (%) of the 4% 24% sub-pulse Peak powerof the 6 90 sub-pulse (W) Energy of the sub-pulse (mJ) 0.1 1.5 Totalenergy of the train 0.4 120.0 of pulses (mJ) Number of pulses per train4 80 (i.e. per composite pulse) Spot diameter (μm) 150 150 Spot area(cm²) 0.0001767146 0.0001767146 Fluence of the single 0.57 8.49sub-pulse (J/cm²) Fluence of the composite 2.26354 679.06109 pulse(J/cm²) Average power (W) 4 60 Dwell time (μs) 100 2000

Table 3 below gives a possible combination of parameters for anexemplary embodiment of a pulse according to the invention.

TABLE 3 Repetition frequency (Hz) 40,000 Duration of the sub-pulse (μs)25 On time of the sub-pulse (μs) 3 Off time of the sub-pulse (μs) 22Duty Cycle (%) of the sub-pulse 12% Peak power of the sub-pulse (W) 45Energy of the sub-pulse (mJ) 0.75 Total energy of the train of pulses(mJ) 30.0 Number of pulses per train (i.e. per composite pulse) 40 Spotdiameter (μm) 150 Spot area (cm²) 0.0001767146 Fluence of the singlesub-pulse (J/cm²) 4.24 Fluence of the composite pulse (J/cm²) 169.76527Average power (W) 30 Dwell time (μs) 1000

FIG. 9 schematically shows the trend over time of the laser emission inan improved embodiment of the invention. Once again, the time isindicated on the abscissa and the power emitted is indicated on theordinate. As can be seen in the diagram of FIG. 9, in this case eachlaser pulse is still a composite pulse, in the sense that emission isnon-continuous in the emission time interval τ-on, but rathercharacterized by sub-pulses. Hereinafter, the composite pulse of FIG. 9is named D pulse and is indicated with DP. FIG. 9 shows a sequence ofpulses DP with the period T. A period T has an on-interval τ-on and anoff-interval τ-off. The sum of the time intervals τ-on and τ-off isequal to the period T of the pulse DP. The relation τ-on/T is defined asthe duty cycle of the composite pulse DP. The inverse 1/T of the periodT of the composite pulse DP is defined as the frequency of the compositepulse DP.

According to some embodiments the frequency of the composite pulse DP,hereinafter also defined as base frequency, is comprised between 1 and1000 Hz, for example between 1 and 500 Hz. The duty cycle of thecomposite pulse DP can be comprised between 1% and 90% and preferablybetween 2% and 50% and even more preferably between 2% and 40%.

As can be observed in FIG. 9, the interval τ-on of each composite pulseDP contains: a sub-pulse of greater duration and a train of sub-pulsesof lesser duration, preferably equal for each of said shortersub-pulses. Hereinafter the sub-pulse of greater duration will beindicated as pre-pulse (Pi) or hyper-energy pulse and the subsequentsub-pulses of lesser duration will be indicated as sub-pulses orhypo-energy pulses Si. The portion of the on interval τ-on of thecomposite pulse DP that follows the pre-pulse Pi is hereinafter alsocalled “tail”. Therefore, each composite pulse DP is in turn constitutedby a pre-pulse Pi, by a train of sub-pulses Si and by an off intervalτ-off. According to one aspect, hyper-energy pulse is intended as apulse with an energy per unit of surface area such as to generate plasmato remove the epidermis but such as not to interact with the middlelayers of the dermis. Hypo-energy is intended as a pulse or sub-pulsewith an energy per unit of surface area adapted to generate a “cold”ablation, i.e. without plasma or substantially without plasma, but ofsufficient intensity to cause hyperemia and shrinkage of the collagenfibers of the deep levels of the dermis.

In some embodiments, as shown schematically in FIG. 9, the pre-pulse orhyper-energy pulse Pi has a higher peak power than the hypo-energypulses or sub-pulses Si. For example, the peak power of the latter isfrom 15 to 70% lower than the peak power of the former.

It would also be possible for the pulses Si and Pi to have the same peakpower.

The sum of the time intervals τ-on and τ-off is equal to the period T ofthe pulse. The relation τ-on/T is defined duty cycle of the compositepulse. The inverse 1/T of the period T of the composite pulse is definedfrequency of the composite pulse. According to some embodiments, thefrequency of the composite pulse, hereinafter also defined as basefrequency, is comprised between 1 and 1000 Hz, for example between 1 and500 Hz. The duty cycle of the composite pulse can be comprised between1% and 90% and preferably between 2% and 50% and even more preferablybetween 2% and 40%.

In some embodiments the sub-pulses Si have a frequency comprised between1 kHz and 200 kHz. In preferred embodiments, the frequency of thesub-pulses is comprised between 1 kHz and 100 kHz, and even morepreferably between 2 kHz and 50 kHz. In some embodiments the frequencyis comprised between 5 and 45 kHz, for example between 8 and 40 kHz.

In some embodiments, the pre-pulse Pi has a duration comprised between10 and 100 microseconds. In improved embodiments of the invention, thepre-pulse has a duration comprised between 20 and 90 microseconds and inparticular between 40 and 80 microseconds. Currently, the preferredduration of the pre-pulse is comprised between 50 and 70 microseconds.Optimal results were obtained with a pre-pulse duration of around 60microseconds.

The duty cycle of the sub-pulses forming the tail of the pulse DP, i.e.the relation between the period of the sub-pulse, indicated with Ts inFIG. 9, and the duration of the on interval of the sub-pulse Si, isdetermined as a function of the peak power, of the duration τ-on of thecomposite pulse and of the energy per pulse that is required to beemitted at each pulse.

The duty cycle of the sub-pulses can be comprised between 1% and 90%,preferably between 2 and 50%, more preferably between 2 and 40%.

The peak power of the pre-pulse Pi, indicated as “Peak Power” in FIG. 9,can be comprised between 100 and 500 W, and preferably between 150 and500 W. In some embodiments the peak power is comprised between 200 and400 W, for example between 250 and 350 W. It would also be possible toadopt higher peak powers, for example comprised between 250 and 500 W.

The peak power of the sub-pulses or hypo-energy pulses Si can besubstantially lower, for example comprised between 20 and 250 W,preferably between 100 and 250 W.

The energy of the pre-pulse can be comprised, for example, between 10and 40 mJ and preferably between 12 and 25 mJ, even more preferablybetween 12 and 20 mJ.

In some embodiments the total energy of the train of sub-pulses Si iscomprised between 0.4 and 200 mJ, for example between 0.4 and 150 mJ andpreferably between 0.4 and 130 mJ.

The energy of the single sub-pulse Si can be comprised between 0.1 and10 mJ and preferably between 01 and 8 mJ.

The number of hypo-energy sub-pulses Si of each composite pulse isvariable for example from 1 to 100 and preferably is greater than 1 andequal to or lower than 80. The spot area, i.e. the area of the sectionof the laser beam on the surface on which the beam is projected, isadvantageously comprised between 0.0001 and 0.0003 cm² and preferablybetween 0.00015 and 0.0002 cm². According to some embodiments thediameter of the spot is comprised between 50 and 500 micrometers,preferably between 80 and 400 micrometers, even more preferably between100 and 200 micrometers, for example around 150 micrometers.

The fluence, i.e. the energy per unit of surface area, is obtained asthe ratio between the powers and the spot areas indicated above and canbe calculated for the pre-pulse or hyper-energy pulse Pi, for eachsub-pulse or hypo-energy pulse Si and for the whole train of sub-pulsesSi, on the basis of the spot area and of the energy emitted in theinterval considered (Pi, single Si or sum of the pulses Si).

The following tables 4 and 5 each indicate two series of values for themain parameters of the pulse. It must be understood that each parametermay vary in the interval defined by the two values of the correspondingline.

TABLE 4 Repetition frequency of the sub-pulse Si (Hz) 10,000 10,000Duration of the sub-pulse (μs) 100 100 On time of the sub-pulse Si (μs)4 24 Off time of the sub-pulse Si (μs) 96 76 Duty Cycle (%) 4% 24% Peakpower pulse Si (W) 100 250 Energy of the single sub-pulse Si (mJ) 0.46.0 Sum of the energy of the train of pulses Si (mJ) 0.4 120.0 Number ofthe pulses Si in a composite pulse 1 20 Spot diameter (μm) 150 150 Spotarea (cm²) 0.001767146 0.0001767146 Fluence of the single sub-pulse Si(J/cm²) 2.26 33.95 Total fluence of the train of pulses Si (J/cm²) 2.26679.06 Average power (W) 4 60 Average power pulse 154 67.5 Dwell time(μs) 100 2000

TABLE 5 Repetition frequency of the sub-pulse Si (Hz) 40,000 40,000Duration of the sub-pulse (μs) 25 25 On time of the sub-pulse Si (μs) 16 Off time of the sub-pulse Si (μs) 24 19 Duty Cycle (%) 4% 24% Peakpower of the pulse Si (W) 100 250 Energy of the single sub-pulse Si (mJ)0.1 1.5 Sum of the energy of the train of pulses Si (mJ) 0.4 120.0Number of the pulses Si in a composite pulse 4 80 Spot diameter (μm) 150150 Spot area (cm²) 0.0001767146 0.0001767146 Fluence of singlesub-pulse Si (J/cm²) 0.57 8.49 Total fluence of the train of pulses Si(J/cm²) 2.26 679.06 Average power (W) 4 60 Average power pulse 154 67.5Dwell time (μs) 100 2000

The following table 6 indicates an example of the values of theaforesaid parameters:

TABLE 6 Repetition frequency of the sub-pulse Si (Hz) 40,000 Duration ofthe sub-pulse (μs) 25 On time of the sub-pulse Si (μs) 3 Off time of thesub-pulse Si (μs) 22 Duty Cycle (%) 12% Peak power of the pulse Si (W)23 Energy of the single sub-pulse Si (mJ) 0.375 Sum of the energy of thetrain of pulses Si (mJ) 15.0 Number of the pulses Si in a compositepulse 40 Spot diameter (μm) 150 Spot Area (cm²) 0.0001767146 Fluence ofthe single sub-pulse Si (J/cm²) 2.12 Total fluence of the train ofpulses Si (J/cm²) 84.88 Average power (W) 15 Average power pulse 30Dwell time (μs) 1000

Table 7 below indicates an example of the values of the significantparameters of the pre-pulse or high energy pulse Pi, usable incombination with the parameters of the pulses Si indicated above:

TABLE 7 On time of the sub-pulse Si (μs) 60 Peak power of the pulse Pi(W) 300 Energy of the single sub-pulse Pi (mJ) 15 Spot diameter (μm) 150Spot Area (cm²) 0.0001767146 Fluence of the single sub-pulse Pi (J/cm²)84.88 Average power (W) 250

The period T of the composite pulse is given by the sum of theoff-period τ-off and of the on-period τ-on, in turn given by the sum ofthe periods of the pulses Pi and Si. The off-period can be comprisedbetween 0.1 and 5 ms, preferably between 0.5 and 2 ms, and even morepreferably between 0.8 and 1.2 ms, for example around 1 ms.

Given a portion of epidermis to be treated, the treatment is carried outby “firing” a train of pulses SP or DP in a plurality of pointsaccording to a given pattern on the surface to be treated. The dwelltime of the laser in a given point of the pattern determines, togetherwith the repetition frequency of the composite pulses (i.e. the inverseof the period T) the number of composite pulses applied in a given pointof the pattern.

The spacing of the points for applying the laser beam can be comprisedbetween 50 micrometers to 1000 micrometers and preferably between 90 and550 micrometers.

For sufficiently high laser intensities and very short laser pulsedurations, the laser-tissue interaction process is mediated by theformation of plasma in proximity of the irradiated surface. Plasma isdefined as a macroscopically neutral gaseous phase with a large fractionof ionized particles.

In the optical breakdown process, the photons of the laser pulsegenerate, in the vicinity of the irradiated surface, a certain number ofelectrons due to ionization of the molecules that have absorbed them;the intense electrical field of the laser pulse accelerates them greatlyand, in a few nanoseconds, the avalanche ionization process that beginscan enable very large electron densities, in the order of 10²⁰electrons/cm³ (dense plasma) and very high plasma temperatures, in theorder of 10⁴° C., to be reached. In these conditions, the plasma isoptically opaque, with subsequent shielding of the surface of the tissuefrom the incident beam, due to the high absorption coefficient of theionized region. Subsequent expansion of the plasma generates a shockwave, which can cause fragmentation and local breakdown of the tissue.

FIG. 17 (taken from Green H A, Domankevitz Y, Nishoka N S. Pulsed carbondioxide laser ablation of burned skin: in vitro and in vivo analysis.Laser Surg Med. 1990; 10(5):476-84) shows the percentage of plasmaformation as a function of the fluence of the CO₂ laser. As can benoted, for pulses with energy density comprised between 40-50 J/cm² thepercentage of plasma is very high and the cut is mediated by the plasmaitself. Instead, for pulses with low fluence 1-10 J/cm² the percentageof plasma is more or less negligible and the cut is mediated mainly bylaser radiation. In the first case, it is the plasma, generated by thelaser itself that produces its biological effects, while in the secondcase, the laser beam vaporizes the tissue directly. In the first casethe temperatures involved are very high, in the order of 10,000° C. withvery short dwell times (ns). In the second case, the temperaturesinvolved are in the order of 1,500-2,000° C. but the times are longer(ms). The biological effects obtained in the two cases are verydifferent from each other.

Plasma vaporization is generally preferred to laser vaporization due toits high precision, the very clean residual tissue (as it inducesminimum lateral thermal damage) and, above all, due to the almost totalabsence of charring. In fact, for example in corneal surgery, where theprecisions involved must be extremely high, plasma ablation is currentlythe absolute gold standard. Moreover, when high peak intensities areused, besides being affected by non-negligible thermal effects, laserablation also suffers from photomechanical effects that limitcontrollability of the cut by the operator. Instead, in the case of thepresent invention the photomechanical effects are a positive element assynergistic with the thermal effects for the desired shrinkage of thecollagen fibers to be induced to obtain tissue shrinkage.

The main object of some embodiments of the invention is to reach thedeep layers of the dermis with the least possible heat front, to inducethe least possible lateral thermal damage but, at the same time, whichis able to stimulate hyperemia and shrinkage of the collagen fibers. Itis known that both phenomena can be activated at medium-lowtemperatures, i.e. in the interval of 40-70° C. Pulses above thethreshold of around 19 J/cm² are capable of generating plasma andtherefore generate, in the ablation cavity, temperatures of over 7,000°C. Around the ablation cavity generated by the plasma (hemisphericalshaped), the matter is so destructured that lateral thermal damage isminimum and the tissue is unable to contract. In fact, the collagenfibers are destroyed and the capillaries are dehydrated (for this reasonthere is no bleeding despite reaching the papillary dermis).

The pulse structured according to the present invention makes use of ahyper-energy laser pulse capable of generating plasma to ablate theportion of epidermis with the least possible lateral thermal damage,thereby reducing to minimum correlated collateral effects, such asre-epithelialization defects due to the presence of carbonaceousresidues or to excessive lateral thermal damage. However, on the otherhand, excessive increase in heat around the ablation cavity causeswidespread collagen destructuring, and in order to find collagen capableof contracting and functional capillaries it is necessary to move awayfrom the ablation cavity by at least a hundred micrometers.

Vice versa, pulses under 19 J/cm² on average cause a minimum ablationcavity, ensure collagen contraction (shrinkage) even around the ablationcavity and however induce minimum vasodilation of the capillaries as theenergy content emitted is decidedly low.

To overcome this limit the stack technology was introduced in the past;this involves multiple repetitions of the aforesaid low energy pulses oneach point. This made it possible to reach considerable depths, but tothe detriment of tolerability, going against the minimally invasivelogic of fractional technology.

Starting from these considerations, with a pulse structured according tothe present invention it is possible to eliminate the drawbacks of priorart and significantly increase the results on treated tissue. Inparticular, the D-type pulse defined above enables plasma mediatedablation to be combined with laser ablation.

As plasma is photo-absorbent and reduces the ablation efficiency of thelaser, the ideal fluences to obtain “cold” laser ablation vary in theinterval of 4-19 J/cm². Acting with fluences in this interval, 20-40 μmof tissue per pulse is removed. In the D-type pulse, a series ofhypo-energy sub-pulses Si (4-19 J/cm²) forming the tail of the compositepulse, is preceded by a single hyper-energy pulse (40 J/cm²) (pre-pulsePi) capable of generating plasma to remove the epidermis but not such asto interact with the middle layers of the dermis. The hyper-energypre-pulse Pi is then followed by a train of ablative hypo-energy laserpulses or laser sub-pulses Si, capable of generating “cold” ablation,but also of efficaciously inducing the hyperemia and shrinking effectsof the collagen fibers located in the deep levels of the dermis.

According to some embodiments the D-type composite pulse is designed bya hyper-energy body or pre-pulse Pi which, according to the curveselaborated by Green (FIG. 17), is capable of generating only plasma.This pre-pulse Pi is followed immediately by a tail of sub-pulses Si,i.e. small hypo-energy pulses. In some embodiments the hyper-energypre-pulse is characterized by an energy of 15 mJ, by an on-time τ-on of60 μs, by a peak power of 250 W, by a spot (i.e. a circular area ofincidence on the skin) with a diameter of 200 μm and consequently by anenergy per unit of surface area of 47.7 J/cm². The subsequent sub-pulsesSi can be characterized by an energy per pulse of 3 mJ, by anon-interval of 24 μs, by a peak power again equal to 250 W, by a spotdiameter of 200 μm and consequently by an energy per unit of surfacearea of 9.5 J/cm².

The concept underlying the invention relates in general toimplementation of a technology which is the result of combiningdifferent technologies with one another, in virtue of the knowledge ofthe various physical-biological phenomena taking place, according toprecise relations of proportionality, both time- and space-related.

In this regard, again within the scope of regenerating and rejuvenatingcosmetic treatments or of treatment for disfiguring scarring, it wouldalso be possible to combine medical products, such as gels containinggrowth factors or bio-stimulating pharmaceutical products, withfractional technology. The limit of conventional fractional technologyconsists in the chemical-physical characteristics of lateral thermaldamage induced by laser ablation not mediated by plasma. In fact, inthese conditions the residual tissue is subject to hyalinizationphenomena and represents an obstacle to the diffusion of the aforesaidproducts applied to the epidermis after laser treatment.

These limits are overcome by the use of an S-type pulse as definedabove. As indicated above, the S-type pulse comprises a series ofsub-pulses, for example characterized by a spot diameter of 150 μm andby an energy per unit of surface area comprised between 1 and 35 J/cm²,for example comprised between 2 and 20 J/cm², preferably between 2 and15 J/cm². These sub-pulses are therefore characterized by energies justabove the threshold for significant plasma formation. In fact, plasma isphotoabsorbent and therefore it would be counter-productive to emitenergy per pulse greatly above this threshold. At these fluences thepercentage of pulses forming plasma is significant and, according toGreen (1990), is around 30%. A pulse thus obtained, as can be observedin the histologies, induces the formation of a hemispherical shapedcrater. The main characteristic, which can be observed histologically,is that this crater is “clean”, with negligible thermal damage andoptimal elasticity both of the margins and of the edges of the cavity.All this can contribute to make the cavity extremely receptive to theapplication of optional medicated products.

Characteristics of the RF Current

As described with reference to FIGS. 6 and 7, the optical radiationgenerated by the laser source can be combined with the application ofradiofrequency current through at least one electrode. The electrode ispreferably integral with the same handpiece on which the laser emitteris located. Although a second electrode for closing the electricalcircuit can also be provided, to be applied at a distance from thefirst, for example as an electrode to be placed in connection with alimb of the subject to which the treatment is applied, to obtain aconcentration of the currents in the zone of the tissue to be treated,which is located in the zone of incidence of the laser beam, it ispreferable to use two electrodes placed close to each other, preferablyboth carried by the same handpiece that also carries the laser emitter.In some embodiments, as shown in FIG. 6, the electrodes are adjacent tothe zone irradiated by the laser source.

In some embodiments the radiofrequency current has a frequency comprisedbetween 50 and 1000 kHz and preferably between 100 and 700 kHz. Incurrently preferred embodiments the frequency of the current iscomprised between 400 and 600 kHz and even more preferably between 450and 550 kHz. Application of the radiofrequency current can normally havea duration that is longer than the laser radiation application time.Typically, the emitting time of the radiofrequency current is comprisedbetween 1 and 10 seconds. In preferred embodiments, the application timeis comprised between 2 and 5 seconds. For reasons that will be apparentbelow, emission of the radiofrequency current does not start beforeapplication of the optical radiation by the laser source. Preferably,application of the laser radiation starts before application of theradiofrequency current. In some embodiments, emission of laser radiationstops before application of the radiofrequency current starts. In fact,the synergistic effect between the application of the two energy formsis presumably achieved as a result of the changes induced by the laseron the vascularized tissue, said changes facilitating the subsequentflow of radiofrequency electrical current in the volume of the tissue inwhich the application of this energy is required.

The power of the current emitted can advantageously be comprised between5 and 100 W. In preferred embodiments the power is comprised between 10and 50 W.

Combination of two different energy forms (optical and RF current),appropriately combined with each other in time and space, enables deeptransfer of the quantity of energy capable of exceeding the activationthreshold of the biological processes typical of tissue repair. Theenergy applied in the form of radiofrequency current emitted separatelywould not be capable of activating any biological process. At the sametime, unless extremely invasive parameters (stack 3-5) are used, laserradiation alone would not be capable of reaching the reticular dermis ina quantity sufficient to significantly activate these processes.

Particularly advantageous embodiments of the invention provide forsymbiotic energy combination so as to obtain a synergistic biologicaleffect of the two energy forms, optical (laser) and electric(radiofrequency current). In other words, this combined emission ofdifferent energies, optical and RF current, gives rise to greaterbiological effects than the simple sum of the single energies emitted.Therefore, the time relationship between the single elements involved isimportant.

With reference to the rationale of the origin of the D-pulse, comprisinga plasma ablation hyper-energy pre-pulse followed by a train ofhypo-energy sub-pulses with laser-ablation effect, it can be observedthat the RF current flows from the intact epidermis, due to the heatwave of the proximal portion of the ablation cavity generated by theplasma, to the ablation cavity generated by the laser pulse and fromhere jumps easily into the dilated capillaries that surround said cavity(see FIG. 12C).

The current jump directly from the epidermis to the surface capillariesis more difficult as these are located at about a hundred micrometersfrom the healthy epidermis and from the ablation cavity generated by theplasma. The sequence of the phenomena, laser ablation and RF currentapplication, is very important for optimizing the phenomenon.

The application sequence, i.e. the time relations between the energiesinvolved, plays an important role in the combination of the two energyforms. According to a possible interpretation of the action mechanism ofthe two energy forms applied, which is indicated here to provide anexplanation of the synergistic effects obtained with the invention, butwhich must not be considered limiting, there is a close correlationbetween the two energies, dependent on concatenation of the biologicalevents caused by them, which cannot be neglected to obtain a hightreatment efficiency. The loss of efficiency could result in anunbalanced or excessive energy emission, which goes against theprinciples that inspire fractional technology with RF.

According to a possible interpretation of the phenomena caused bycombined emission of the two energy forms, which is provided here aspossible explanation, but which the concepts underlying the inventionare not bound to or dependent on, after laser ablation (mediated or notby plasma) a transitory ischemia followed by persistent hyperemiaoccurs, as represented schematically in FIG. 18.

In the diagram of FIG. 18 the time is indicated in the abscissa. Asshown in the figure, the laser pulse is followed by a formation ofvapors and plasma and by an ischemia of the tissue in the time intervalfrom 0.01 to 0.1 seconds after the rising front of the pulse (in thecase of composite pulses such as those described here, this is intendedas the rising front of the pre-pulse in the case of composite D-typepulse, or the rising front of the first sub-pulse in the case ofcomposite S-type pulse).

In the subsequent 24 hours there is an intense hyperemia of the tissue.Moreover, after the first half second, intense exudation takes place andplugs of exudate and keratin (crusts) form. The diagram shows the trendsover time of the conductivity of the epidermis and of the dermis. Asindicated in the diagram, it can be observed that the conductivity ofthe epidermis is generally greater than that of the dermis up to aninstant (from a few tenths up to more than one second from the start ofapplication of the laser pulse), in which the conductivity values areinverted, with the dermis that becomes more conductive than theepidermis. The instant in time in which the two curves cross over is theoptimal moment for starting application of the energy in the form of RFcurrent. Typically, the radiofrequency current can be applied startingfrom 0.8-1.2 seconds after the rising front of the laser pulse.

In fact, in the preceding instants there is an excessive gap in theconductivity between epidermis and dermis. To obtain a significanttherapeutic effect, this impedance jump imposes the application of veryhigh quantities of RF current, greater than those sufficient if thecurrent is emitted starting from the cross-over point of the aforesaidelectrical conductivity curves.

In this regard, to induce homogeneous hyperemia of the capillaries ofthe papillary dermis, the distribution in space of the heat wavesgenerated by the laser radiation assumes considerable importance. Infact, it is important that the spots are distributed with the greatestpossible distance between them, although still capable of ensuring acertain degree of overlapping of the heat fronts of the dermis. Thisensures that all the capillaries will be involved by the phenomenon ofvasodilation and the current can thus flow adequately through them tothe reticular dermis.

Effects of the New Laser Pulses, Optionally in Combination with RFCurrent

Numerous clinical studies have been carried out to evaluate the effectsof the new shapes of laser pulses described above, separately orcombined with the application of radiofrequency current, in order tohighlight their multiple ameliorative aspects over the prior art.

Typical applications relate to aesthetic treatments of the skin, inparticular with the object of obtaining a reduction of wrinkles, firmingand overall rejuvenation of the tissue.

In order to evaluate the different effects on tissue of the laser pulsesSP and DP described above, in vivo tests were carried out on a sheep.

FIGS. 10A-10K show a selection of the results attained. Each figureindicates the type of pulse used (DP or SP), the duty cycle of thecomposite pulse, indicated as “burst” and expressed in percentage, theenergy emitted per pulse expressed in mJ and the duration inmicroseconds of the composite pulse applied.

The microphotographs illustrated in FIGS. 10A-10K, in particular, showthe effect of tissue ablation at the axis of the optical laser beamapplied and the shrinkage effect. As can be observed from thehistologies in all the photographs indicated in FIGS. 10A-10K, the SPpulse and the DP pulse differ considerably as far as the shape of theablation zone, and shrinkage effect in the tissue surrounding thecentral zone involved, by laser beam, are concerned. The subsequentFIGS. 11A and 11B show a schematic representation of the ablation andshrinkage effect obtained respectively with the SP pulse (FIG. 11A) andwith the DP pulse (FIG. 11B). FIGS. 12A and 12B schematically show theheat bubble that is generated in the tissue in the two cases (FIG. 12Afor the SP pulse; FIG. 12B for the DP pulse).

As can be observed from FIGS. 10-12, the SP pulse generates an ablationzone in the papillary dermis (PD) with modest shrinkage effect, whilethe DP pulse generates an ablation zone, again limited to the layer ofpapillary dermis (PD), but much deeper. The ablation zone is surroundedby a surrounding area in which the papillary dermis has undergonesubstantial contraction or shrinkage. From the viewpoint of heat (FIGS.12A and 12B), it can be observed that the SP pulse generates a heatbubble, i.e. a thermal heating front of the tissue, which involves thethickness of the papillary dermis and laps the reticular dermis RDbelow. The DP pulse, characterized by the pre-pulse and by the tailformed by a sequence of high frequency sub-pulses, generates a heatbubble, i.e. a heat front represented in FIG. 12B, which besides passingthrough the papillary dermis also deeply penetrates the reticular dermisbelow.

FIG. 12C schematically shows the effect of ablation of the opticalradiation in the two modes: direct laser ablation and plasma mediatedablation. The first cavity excavated in the epidermis is generated byplasma mediated ablation (indicated as “plasma ablation cavity” in thefigure). The deepest part of the ablation (indicated as “laser ablationcavity” in the figure) is obtained by direct ablation using the laserbeam. The figure also shows the zones involved by the heat wavegenerated by plasma and by the heat wave generated by laser radiation.As can be observed, the zone hit by the heat generated during the laserablation phase (not plasma mediated) is located at a greater depth fromthe epidermis and penetrates the tissue in which there is greaterdensity of blood vessels, which as a result of the radiation undergodilation and hyperemia.

The effect of this increased penetration is an intense stimulation ofthe blood supply and consequently intense hyperemia of the tissue.Thermal stimulation of the reticular dermis also causes increasedshrinkage of the surface layers of the papillary dermis.

The results illustrated above refer to applications of laser energyalone. The combination of laser radiation (emitted in the form ofcomposite DP-type or SP-type pulses) with the emission of radiofrequencyelectrical current makes it possible to obtain an improvement of thetreatment effects.

Penetration of the radiofrequency current in the tissue depends on thefrequency of the current applied, on the magnetic permeability of thetissue and on the conductivity of the tissue according to the formula:

$\delta = \frac{1}{\sqrt{\pi\; f\;\mu\;\sigma}}$where:δ is the standard penetration depth expressed in mπ=3.14f is the frequency in Hzμ is the magnetic permeability expressed in Henry per meterσ is the electrical conductivity expressed in Siemens per meter.

FIG. 13 shows the trend of the electrical conductivity (expressed inS/m) as a function of the frequency of the current for the followingtissues or structures:

BV: blood vessels

WS: wet skin

F: adipose tissue

DS: dry skin

It can be observed in the diagram of FIG. 13 that the maximumconductivity is that of the blood vessels.

In the absence of ablation treatment and of vasodilation, theradiofrequency current flows for about 90% through the epidermis andonly for 10% along the blood vessels. Following stimulation of thetissue by laser irradiation and above all as a result of ablationresulting from irradiation of the epidermis with the laser pulses, asubstantial improvement of the radiofrequency current flow conditions isobtained.

Vasodilatation is mainly due to two effects: a first immediate effect isheating due to the heat wave. Heating of the blood vessels causesimmediate vasodilation as a result of thermal effect. A second slowerand more persistent effect is due to the action of the laser onneuro-modulating factors. This effect occurs with a delay compared tothe first and has greater persistence over time.

Regardless of which of the two effects are used, vasodilationcontributes to an increased flow of current through the blood vesselsand consequent reduction in the flow of current in the surface layers(epidermis) of the skin. This is due both to the decrease in thedistance between vessel walls and outer surface of the epidermis, and tothe increased cross section of the vessel. Moreover, the formation ofablation cavities reduces locally, i.e. at the micro-hole obtained bythe laser ablation effect on the tissue, the distance between outersurface of the epidermis and blood vessels. This enables more efficientdeep penetration of the radiofrequency current. The formation of plasmain the ablation cavity, resulting from the localized increase intemperature caused by the laser, further improves electricaltransmission.

Typically, from a distribution of 90% of current on the surface and 10%in the blood vessels, a distribution of around 60% of the radiofrequencycurrent flowing at the level of the epidermis and 40% at the level ofthe blood vessels can be obtained as a result of the application oflaser energy.

This increased flow of electrical current in the deep tissues causesdeep hyperemia. This deep hyperemia in turn supplies the hyperemia ofmore superficial tissue, even after emission of energy from the outsidehas ceased.

The quantity of hemoglobin provides an indication of the level of tissuehyperemia. FIGS. 14A to 14E show diagrams of the trend of the variationin percentage of hemoglobin over time following treatment with laser orwith laser and radiofrequency current according to the invention. Thediagrams highlight the different effect of the various types oftreatment with one or other of the two SP and DP pulses described above,with or without the application of radiofrequency current. The trendover time of the percentage of hemoglobin is indicative of the trendover time of the hyperemia. With an increase in blood flow, andconsequently of hyperemia, there is an increase in hemoglobin. Theabscissa indicates the time (not in scale) from the treatment and theordinate indicates the variation in the percentage of hemoglobinstarting from a base value corresponding to the origin of the ordinate(hemoglobin content before the treatment).

The parameters used to obtain the results indicated in these figures arethe following:

average pulse power: 30 W

peak power: 250 W

D-pulse with pre-pulse Pi of 60 microseconds followed by 40 sub-pulsesSi;

S-pulse with 40 sub-pulses

Stack 1 (one composite pulse)

Dwell time 1 ms

Energy per pulse 0.75 mJ

Radiofrequency energy: 30 W for 3 seconds at 500 kHz.

More in particular, FIG. 14A indicates two curves, marked with SP andDP, which show the trend of the variation of hemoglobin percentage overtime following treatment with laser alone with SP-type pulses and withDP-type pulses respectively, without the application of radiofrequencycurrent. It can be observed that in both cases the quantity ofhemoglobin increases following the treatment and has a peak at around18-20 hours after the treatment. However, in the case of treatment withDP-type pulse, the peak is much lower. In practice, this corresponds toa lower impact of the cosmetic treatment on the patient and consequentlyfewer negative side effects, such as reddening and swelling.

After passing the hyperemia peak within 24 hours from application, thehemoglobin values drop to levels that exceed the base values(pre-application) by less than 40%. However, it is noted that in thelong term, more than 72 hours after the treatment, the hyperemia causedby treatment with DP-type pulses tends to remain above the base value,increasing slightly, while hyperemia caused by conventional pulses tendsto decrease, returning toward the pre-application value.

In practice, this means that the treatment with DP pulses is lessinvasive, causing fewer undesirable side effects in the short time, butmaintains the level of hyperemia at values above normal for longertimes. This enables a longer lasting effect of stimulation of thebiological processes that lead to the desired results of rejuvenationand toning of the tissue.

FIG. 14B compares the effects on the percentage content of hemoglobinobtained by the application of laser energy with SP pulse (SP curve)with those obtained by the combined application of laser pulses ofSP-type and radiofrequency current.

It can be observed that by applying radiofrequency in combination withthe SP-type pulse, there is a further reduction of the peak of increaseof hyperemia. Therefore, an advantage of reduction of side effects isobtained in the short term (around 24 hours from application).

In the long term (over 72 hours) an increased hemoglobin content isobserved, which indicates an increased degree of hyperemia over time, inthe case of combined laser+RF treatment. This corresponds to the factthat the energy emitted through radiofrequency caused a deeperhyperemia, as the vasodilation caused by pre-treatment with the laserpromoted the flow of electrical current in the deeper layers of thetissue, to the detriment of the flow in the outer layers of theepidermis. The deep hyperemia thus induced maintains a longer lastingeffect over time, although reducing the hyperemia peak in the shortterm.

FIG. 14C compares the effect, in terms of variation of the percentage ofhemoglobin content, of the laser beam with DP pulses alone (DP curve)and of the laser beam with DP pulses in combination with radiofrequency(DP+RF curve). It can be observed that the hyperemia peak in the 24hours remains substantially unvaried, i.e. it is not influenced eitherpositively or negatively by the combined application of laser energy andradiofrequency electrical energy. In the long term, a minimum is reachedfollowed by an increase in both cases, with a steeper trend in the caseof combined application.

The curves DP+RF and SP+RF of FIG. 14D show the trend of the variationsof hemoglobin percentage over time in the case of combined applicationof laser+RF current in the two cases of SP pulse (SP+RF curve) and of DPpulse (DP+RF curve).

Finally, FIG. 14E shows overlapping of the four curves SP, DP, SP+RF,DP+RF. An ideal curve Id, indicated with a dashed line, is overlapped onthese four curves; this represents the ideal trend that the hyperemiashould have to obtain minimum undesirable side effects and maximumtreatment efficacy. It can be observed that the use of a DP pulse, orthe combined use of one of the two DP or SP pulses with the applicationof radiofrequency current provides hyperemia curves which are closer tothe ideal curve and therefore more favorable. In particular, it can beobserved that the shape of the DP pulse enables, even without theapplication of radiofrequency current, a particularly efficient resultto be obtained in terms of trend over time of the hyperemia.

A hyperemia that lasts over time enables more efficient tissue repair tobe obtained as a result of the effect of the hyperemia on pH values,temperature, NO, ptO₂, ptCO₂, O₂, activation of cellular redoxcomplexes, acute phase proteins, cytokines, cellular proliferationspeed, cellular differentiation and cellular renewal speed.

Besides the effects in terms of inducing hyperemia, and the trend overtime thereof, another important factor in evaluating the efficacy ofthese treatments is the shrinkage effect on tissue and in particular oncollagen. Shrinkage is an effect of considerable importance intreatments to rejuvenate the epidermis, reduce wrinkles, and to tone andfirm tissue.

Tests performed using the various combinations of pulses SP, DP andSP+RF, DP+RF gave results that are variable as a function of the type oftreatment carried out. The degree of shrinkage can be determined simplyby measuring the distance between points of the treatment pattern at thetime of application and in a time interval subsequent to application.FIG. 15 indicates in the ordinate the average distance between thepoints of the pattern, i.e. the average distance between the centers ofthe marks of the laser beam for the four possible combinations indicatedin the abscissa:

SP: laser alone with SP pulse

DP: laser alone with DP pulse

SP+RF: laser with SP pulse in combination with radiofrequency current;

DP+RF: laser with DP pulse in combination with radiofrequency current.

The diagram indicates squares labelled Im and 120. The former indicatethe values immediately after treatment, i.e. indicative of the shrinkageobtained as an immediate effect of the treatment on the tissue. Thesquares indicated with 120 indicate data collected 120 hours aftertreatment. The statistical significance of the data is marked with (***)(=significance greater than 99%) and ns (statistically insignificantdata).

In the diagram of FIG. 15 it can be observed that in the long term theeffect in terms of shrinkage is greater in the case of combinedlaser+radiofrequency treatment, regardless of the type of laser pulse(SP, DP) used.

The excellence of the treatment is also determined as a function of thetime required for complete recovery of the subject treated, i.e. thetime necessary for the traces of the treatment to disappear from theepidermis. The experimental results relating to this aspect are summedup in the diagram of FIG. 16.

In this diagram the abscissa indicates the time expressed in days sincetreatment (origin of the abscissa). The ordinate indicates thepercentage of plugs of exudate and keratin, hereinafter improperlycalled “crusts”, which persist over time. Immediately after thetreatment 100% of the crusts are visible. The four curves indicated withDP+RF, SP+RF, DP and SP show the trend over time of the reduction in thenumber of crusts. It can be observed in the graph that the treatmentwith laser alone and SP pulse causes greater persistence of thesecrusts, while combined treatment of laser radiation with DP-type pulseand radiofrequency current is characterized by a substantial decrease inthe time required for the disappearance of a high percentage (80%) ofthe crusts. In the case of treatment with DP pulses and radiofrequency,over 80% of the crusts had already disappeared 8-9 days after treatment,while in the case of application of laser alone with SP pulses the samelevel of decrease is only reached 13 days after treatment.

While the embodiments described of the object illustrated here have beenshown in the drawings and described in full in the above withparticulars and details in relation to the different examples ofembodiment, those skilled in the art will understand that a number ofmodifications, changes and omissions are possible without departing fromthe innovative teachings, from the principles and from the concepts setforth above, and from the advantages of the object defined in theappended claims. Therefore, the effective scope of the innovationsdescribed must be determined only on the basis of the widestinterpretation of the appended claims, so as to comprise allmodifications, changes and omissions. In addition, the order or sequenceor any step of the method or process can be varied or rearrangedaccording to alternative embodiments. In particular, it is possible toobtain the above-described synergistic effects from combination of thelaser radiation and of the radiofrequency current also using othershapes of laser pulse, such as a sequence of simple pulses, withappropriate repetition frequency.

DIDASCALIE FIGURE

FIG. 8 e FIG. 9: Peak power/Stay time

FIG. 11 e 12 (A) e (B): PULSE S/Papillary dermis/reticular dermis

FIG. 12 (C): Laser ablation cavity/plasma ablationcavity/epidermis/hyperemic vessels/plasma heat wave/laser heat wave

FIG. 13: Conductivity/Frequency

FIG. 14: hours

FIG. 15: Shrinkage

FIG. 16: days

FIG. 17: Plasma formation

FIG. 18: the delta is too high and therefore the current density in thedermis is too low/Conductivity epidermis/conductivity dermis/plasma &vapors/laser pulse/vapors/exudation and plug/ischemia/hyperemia

The invention claimed is:
 1. A system for treating a region of theepidermis, the system comprising: at least one laser energy source; atime control device configured to generate a laser beam comprising aplurality of composite pulses, each of said composite pulses beingemitted at a base frequency, each of said composite pulses comprising asequence of sub-pulses, said sequence of sub-pulses being emitted at afrequency that is higher than said base frequency, each of saidcomposite pulses comprising a first interval of continuous pre-pulseemission followed by a sub-pulse sequence emission interval, saidsub-pulse sequence emission interval comprising a train of sub-pulsesfollowing said pre-pulse emission, said first interval of continuouspre-pulse emission comprising a first interval pre-pulse emissionduration, each of said subsequent sub-pulses having a sub-pulseduration, said first interval pre-pulse emission duration being greaterthan said sub-pulse duration of each of said sub-pulses; a laser energyfocusing system arranged and configured to direct said laser beam onsaid region of the epidermis.
 2. The system according to claim 1,wherein said base frequency is comprised between 1 and 1090 Hz.
 3. Thesystem according to claim 1, wherein said composite pulse comprises apre-pulse with a higher energy per surface unit than said sub-pulses. 4.The system according to claim 1, wherein said pre-pulse emission has ahigher peak power than a peak power of the subsequent sub-pulses.
 5. Thesystem according to claim 1, wherein said laser energy focusing systemis arranged and controlled to treat contiguous volumes of the epidermisdistributed according to a pattern, wherein each volume treated has acenter substantially positioned on an axis of the laser beam used totreat said volume, wherein axes of laser beams used to treat saidcontiguous volumes are distributed according to a presettable matrix ofpoints.
 6. The system according to claim 5, wherein said focusing systemis arranged and designed to direct one or more laser beams according topitches spaced from one another from 50 micrometers to 1000 micrometers.7. The system according to claim 1, further comprising a radio frequencycurrent source and at least one electrode for applying a radio frequencycurrent.
 8. The system according to claim 7, further comprising anotherelectrode to provide two electrodes for applying the radiofrequencycurrent.
 9. The system according to claim 7, wherein said radiofrequencycurrent source and said at least one laser energy source are controlledso as to apply a radiofrequency current generated by said radiofrequency current source coordinated in time with application of saidlaser beam.
 10. The system according to claim 9, wherein saidradiofrequency current source and said at least one laser energy sourceare coordinated in time so as to apply a radiofrequency current at leastpartly simultaneously to, and/or in a sequence with, the application ofsaid laser beam.
 11. The system according to claim 7, wherein saidradiofrequency current source is controlled to apply a radiofrequencycurrent for a time comprised between 1 and 10 seconds, on a portion ofepidermis, in combination with application of said laser beam.
 12. Thesystem according to claim 7, wherein said radiofrequency current sourcegenerates a current at a frequency comprised between 50 and 1000 kHz.13. The system according to claim 7, wherein said radiofrequency currentsource applies a power comprised between 5 and 100 W.
 14. The systemaccording to claim 7, wherein said radiofrequency current source iscontrolled to start to emit with a time delay from 0.1 to 1.5 secondsfrom a start of laser emission.
 15. The system according to claim 7,wherein said at least one electrode comprises a means for reducing orpreventing formation of electric discharges between the at least oneelectrode and a tissue to be treated.
 16. The system according to claim1, wherein said at least one laser energy source has a wavelengthcomprised between 532 and 13,000 nm.
 17. The system according to claim16, wherein said at least one laser energy source is a CO2 laser withemission at 10600 nm.
 18. The system according to claim 1, furthercomprising a scanning device to direct said laser beam on multiplepoints of a portion of epidermis to be treated, spaced from one another.19. The system according to claim 1, further comprising a waveguide toconvey laser energy from said at least one laser energy source towardsan applicator handpiece.
 20. The system according to claim 19, furthercomprising a scanning device to direct said laser beam on multiplepoints of epidermis to be treated, spaced from one another, wherein saidscanning device is housed in said applicator handpiece.
 21. The systemaccording to claim 7, further comprising a waveguide to convey laserenergy from said at least one laser energy source towards an applicatorhandpiece, wherein said at least one electrode for applyingradiofrequency current is carried by said handpiece.
 22. The systemaccording to claim 8, wherein said handpiece carries said two electrodesfor applying radiofrequency current.
 23. The system according to claim2, wherein said composite pulse comprises a pre-pulse with a higherenergy per surface unit than said sub-pulses.
 24. The system accordingto claim 2, wherein said pre-pulse emission has a higher peak power thana peak power of the subsequent sub-pulses.
 25. The system according toclaim 3, wherein said pre-pulse has a higher peak power than a peakpower of the subsequent sub-pulses.
 26. The system according to claim 5,wherein said focusing system is arranged and designed to direct one ormore laser beams according to pitches spaced from one another from 90 to550 micrometers.
 27. The system according to claim 7, wherein saidradiofrequency current source is controlled to apply a radiofrequencycurrent for a time comprised between 2 and 5 seconds on a portion ofepidermis, in combination with application of said laser beam.
 28. Thesystem according to claim 7, wherein said radiofrequency current sourcegenerates a current at a frequency comprised between 100 and 700 kHz.29. The system according to claim 7, wherein said radiofrequency currentsource generates a current at a frequency comprised between 400 and 600kHz.
 30. The system according to claim 7, wherein said radiofrequencycurrent source generates a current at a frequency comprised between 450and 550 kHz.
 31. The system according to claim 7, wherein saidradiofrequency current source applies a power comprised between 10 and50 W.
 32. A system for treating a region of the epidermis, the systemcomprising: a laser energy source; a time control device configured togenerate a laser beam comprising a plurality of composite pulses emittedat a base frequency, each of said composite pulses comprising a sequenceof sub-pulses, said sequence of sub-pulses being emitted at a higherfrequency than said base frequency, each of said composite pulsescomprising a first interval of continuous pre-pulse emission followed bya sub-pulse sequence emission interval, said sub-pulse sequence emissioninterval comprising a plurality of sub-pulses following said pre-pulseemission, said first interval of continuous pre-pulse emission having agreater duration than each of said subsequent sub-pulses; a laser energyfocusing system configured to direct said laser beam on said region ofthe epidermis.
 33. The system according to claim 32, wherein said basefrequency is comprised between 1 and 1090 Hz.
 34. The system accordingto claim 32, wherein said composite pulse comprises a pre-pulse with ahigher energy per surface unit than said sub-pulses.
 35. The systemaccording to claim 32, wherein said pre-pulse emission has a higher peakpower than a peak power of the subsequent sub-pulses.
 36. A system fortreating a region of the epidermis, the system comprising: a laserenergy source; a time control device configured to generate a laserbeam, said laser beam comprising a plurality of composite pulses emittedat a base frequency, each of said composite pulses comprising acontinuous pre-pulse emission interval followed by a sub-pulse sequenceemission interval, said continuous pre-pulse emission intervalcomprising a continuous pre-pulse emission, said sub-pulse sequenceemission interval comprising a plurality of sub-pulses following saidpre-pulse emission, said continuous pre-pulse emission intervalcomprising a pre-pulse emission interval duration, each of saidsub-pulses comprising a sub-pulse duration, said pre-pulse emissioninterval duration being greater than said sub-pulse duration of each ofsaid sub-pulses, said plurality of sub-pulses being emitted at asub-pulse frequency, said sub-pulse frequency being greater than saidbase frequency, a laser energy focusing system configured to direct saidlaser beam on said region of the epidermis.